Colloidal products are known which are obtained by carbonation of an excess of alkaline earth oxide or hydroxide dispersed in micelles by surface active agents such as sulphonic acids and salts thereof. These products contain an alkaline earth metal carbonate dispersed in colloidal state.
It has already been proposed in the prior art to modify such micelles by different reactions.
In French patent application FR-A-2645168, thiophosphoric compounds are described which are obtained by reaction of a sodium or calcium sulphonate overbased by sodium or calcium carbonate with phosphorus sulphide, generally P.sub.4 S.sub.10, this reaction being possibly followed by reaction with a compound with active hydrogen, which can be water, methanol, isopropanol, a phenol, acetic acid, a dialkylphosphite, boric acid, phosphoric acid, ammonia, an amide, dimercaptothiadiazole, or a derivative thereof. Compounds obtained solubilized in a medium hydrocarbon medium by micellization can be used as wear resistance and extreme pressure additives in lubricating oils.
Furthermore, in published French patent application 2,681,872 (corresponding to published European application 0536020) the applicant describes and claims colloidal products containing boron and phosphorus obtained by a method in which a overbased alkaline or alkaline earth sulphonate containing borax is prepared; this product is reacted with a phosphorus sulphide and the resulting product is separated. These products are also used as wear resistance and extreme pressure additives in lubricating oils and greases. Published French patent application 2689031 (corresponding to published European application 056912) can also be cited, in which colloidal products are described and claimed, which can also be used as wear resistance and extreme pressure additives in lubricating oils. They are defined as being obtained by reaction of an overbased detergent compound (such as an alkaline or alkaline earth sulphonate, phenate, salicylate or naphthenate an overbased by an alkaline or alkaline earth carbonate or hydroxide) with a sulphurated carboxylic acid.
In the cases cited above, modifications brought about to the core of the micelles were partial and residual alkaline or alkaline earth carbonate remained.